Re: 2012 motors?
 

Right. I'm sure FIRST and AM have a pretty rigid NDA in place, but I've got to believe that FIRST and AM have a tight enough relationship at this point that a heads-up would have gone out to them if CIMs were going to be illegal in 2012.

On second thought, I used to think that FIRST and IFI had a tight relationship too, so I could be completely off base on this one...

Re: 2012 motors?
 

There is a perfectly valid reason for AndyMark to have a sale on CIM motors right now, and that's exactly as was stated: to move inventory. Anyone who has ever studied even the very basics of lean business practices and kanban inventory systems knows the problems associated with having large inventories and the resources/capital tied up maintaining them.

I doubt the CIM motor is leaving the 2012 KoP. This motor is fairly cheap, nearly indestructible, and has been long been adopted as the "default" FRC motor: nearly every available FRC-catered COTS gearbox either is designed to use a CIM motor as an input or has been designed to emulate a CIM motor on the output side.

Except for the quality issues relating to the Banebot-specific RS775 motors, I would absolutely love to have the "choose any four" of the same or similar series of motors. The RS775 motors were champs, and while not as indestructible as CIM motors, were significantly more reliable than the 5xx-series Banebot or Fisher Price motors.

And if Bill's Blog's hints of a shorter game manual are any indication, I wouldn't be surprised to see the motor rules follow the same path as pneumatics and have relaxed rules for the 2012 season. After all, I'm sure we're not the only team to have an entire KoP tote filled with past FP, Globe, window, van door, etc motors that are just gathering dust because they're no longer FRC legal.

Re: 2012 motors?
 

I told Mark last night about the speculation on CD caused buy the sale on CIM's and the new CIM-Sim gearbox and he just laughed. He said it was a sale and not a clearance like the other products and smiled.

I think it was Lavery who put them up to it just to cause a ruckus. God help us all if Mark and Andy join in on his shenanigans.

As far as what they know about the game, it is my belief that outside of the GDC Mark probably knows more about the game each year than anyone else. I have tried and tried for years to get info out of him but he is a rock. I doubt if he even tells Andy half of what he knows.

Re: 2012 motors?
 

Miller, not Lavery. Remember that Lavery isn't designing the games any more.

The problem is he taught Bill Miller far too well.

Re: 2012 motors?
 

Trust me your not

Re: 2012 motors?
 

I heard that we are getting 4 waterproof CIM motors in the KOP this year :D

Re: 2012 motors?
 

I wouldn't bet against it.

The CIMs have rubber seals on the case, so they're very water-resistant against splashing. And I bet they'd actually operate reasonably well fully immersed and filled with water. (12 V DC motors aren't actually that sensitive to running in fresh water, at least for short periods.)

Re: 2012 motors?
 

Seriously, where do you guys come up with these? IF they were available they would only be legal on Fourth of July demos in the rain.

Re: 2012 motors?
 

They'd run just fine in properly distilled water. Distilled water is a horrible conductor.

Re: 2012 motors?
 

To play devils advocate (and they're interesting questions to think about):

What happens if/when there gets to be a distilled water film between the brushes and their contacts? Is there a new maximum critical speed if the motor is in water?
What happens when the carbon from the brushes contaminates the water?
How much extra drag will there be (i.e. how much power will you lose) when the water viscously couples the rotator and fixed magnets?
What will happen to the bearings?

My guess is that they won't run fine ;)

Re: 2012 motors?
 

The lubricant in the bearings and the iron oxide from the steel shaft and bearings would be the biggest contribution to contamination.

On a side note, a new transmitter design I saw recently has distilled water in a primary cooling loop for an output tube running 35kV on the anode. The water is filtered and deionized constantly and a sensor checks the conductivity of the water for problems. A person sticking a finger in the water is enough to shutdown the high voltage it is that sensitive. Distilled water has been used for years as cooling. The down side is without anti-freeze, distilled water is prone to freezing in cold weather prior to transmitter reaching operating temperature. I honed my skills on soldering soft copper elbows when an engineer failed to correct a bad temperature relay/sensor in a water cooled transmitter when I was in school. The heat exchanger had 32 elbows that would blow out when the water froze.

Re: 2012 motors?
 

I was hinting towards waterproof because of this year being a water game....

Re: 2012 motors?
 

No argument with regard to the conductivity of water. I was thinking about the longer term, as the water helps to flush the lubrication out of the bushings/bearings, and the really long term as oxidation sets in.

I suspect (though I'm not sure for the CIMs in particular) that the springs that push the brushes into contact the commutator, even after they wear for a while, would be strong enough to prevent any significant film of water from wedging its way between the brush and commutator.

When stuff diffuses (metal ions) or flakes off (carbon) into the distilled water, it will become conductive, just like regular water.

The extra drag is hard to establish. I don't know of any simple way to model this, because of the multiple irregular surfaces. Probably a job for computational fluid dynamics, or better still, an empirical test. The free speed of the motor ought to change as a result, but I don't have a good estimate of how much.

The bearings won't be happy. (However, they will run cooler, in all likelihood, at least for anything approaching an ordinary duty cycle, with ambient conditions that can absorb thermal energy from the motor.) As mentioned above, although oils and greases typically have low solubility in water, the mechanical action of the water will tend to strip them out of the bearings. At that point, it's just low-viscosity water supporting the bearings, which doesn't work so well. Bushings will probably last much longer in this situation, but given even a little solubility (stuff tends to be more soluble in distilled water than ordinary tap water, because there's nothing dissolved in distilled water yet), and a lot of time, they'll probably fail at least somewhat prematurely.

I still think that, for a typical FIRST robot that doesn't see more than 10 h of running in its entire development and competition lifetime, they'd work fine.

Anyone want to volunteer to fill a fresh CIM motor with water, drop it in a bucket, and run it until it dies? (I'm looking at you, Andy Baker: if that AndyMark summer sale is anything to go by, you might just have a few you don't care so much about.)

Re: 2012 motors?
 

As Tristan has pointed out, I suspect a CIM would work fine in distilled water for the length of time required for its application in FRC. Yes, of course there's other issues at play, but I think in the relatively short service life of an FRC motor, it would be fine.

Re: 2012 motors?
 

It's not just the 10 hours of run time, it's calendar time from first exposure to water until the season is over. Rust.